Lens array of distributed absorbers coupled MKIDs for the PRobe far-Infrared Mission for Astrophysics (PRIMA)

Future observatories for the far-infrared (FIR), such as envisioned in the NASA Probe announcement, will offer unprecedented sensitivity by using cryogenically cooled optics. Large arrays of lens-absorber coupled Microwave Kinetic Inductance Detectors (MKIDs) are the only candidate to fulfill the requirements for these observatories, requiring unprecedented sensitivity with a noise equivalent power below 10^(-19) W/√Hz while operating up to 12THz. The incoherent coupling mechanism of distributed absorbers leads to a robustness against misalignment, assembly, and fabrication issues at FIR wavelengths. In this contribution, we will present the design and fabrication of large arrays of lens-absorber coupled detectors and evaluate their performance at 7 and 12THz and demonstrate an NEP of 0.7⋅10^(-19) W/√Hz.